Comparison of Adsorption Characteristics of Different Sorbents for Acetaldehyde and Furfural in Baijiu

The adsorption characteristics of functionalized polystyrene resin for acetaldehyde and furfural in Baijiu were evaluated in comparison with those of other sorbents including activated carbon, diatomite, and AB-8 macroporous resin. The adsorption capacity of the modified polystyrene resin was 60.19 and 47.37 mg/g for acetaldehyde and furfural at 240 min and 323 K, respectively, greatly exceeding that of the other sorbents. Adsorption experiments were conducted on three major commercial flavor types of Baijiu, revealing less than 1% change in the total ester content of Baijiu before and after adsorption, so selective adsorption could be achieved using this sorbent. Its structure was characterized through elemental analysis (EA), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) surface area and pore structure analysis, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The adsorption mechanism of aldehydes and furfural on the functionalized resin was investigated using adsorption kinetics, isotherms, and thermodynamics. The findings indicated that the adsorption process fitted well with the pseudo-second-order model and the Freundlich model. Based on the results of ΔG⁰ > 0, ΔH⁰ > 0, and ΔS > 0, the adsorption was a non-spontaneous endothermic process. As the adsorption process proceeded, the solution became less orderly, and the adsorption process was primarily governed by chemisorption. This research serves as a reference for the quality and health improvement of Baijiu.